1. Field of the Invention
The present invention regards a contactor, particularly a vapour exchanger, to control the air hygrometric content in dehumidification, humidification and air conditioning equipment, on the basis of sorption or desorption phenomena of water vapour taking place with water or with hygroscopic solution from or into an air stream coming from a conditioned environment and/or from or into the indoor air of the environment itself.
2. Description of the Related Art
In the known air handling processes mass exchangers which make use of hygroscopic solutions are brought into direct contact with the air either by percolating and/or spraying the liquid phase in the form of drops/droplets through the air stream or by air bubbling through a filled column. In both cases the air stream is in direct contact with the liquid phase and water vapour exchanges take place between the phases.
According to the specific application involved, the air stream, usually dehumidified by these devices, is then, further treated before being sent, for instance, into the conditioned environment.
These well known direct contact mass exchangers present some inconveniences such as:
the absorption process is limited by the air-liquid dessicant contact area. If the contact area is increased by spraying onto extended surfaces the solution, problem arise when a high viscosity solution has to be used. PA1 the contact area is dependent on both the air and solution flow rate. PA1 air particulates and dust may progressively dirty the hygroscopic solution. PA1 dehumidification or humidification devices have large dimensions and their maintenance and servicing are not easy; PA1 high friction loss along the air path in the case of a filled column. PA1 low friction loss along the air path; PA1 elimination of carryover effects; PA1 a contact area between the phases which is independent from both the solution and the air flow rate; PA1 prevention of any pollution of the hygroscopic solution by dust and particulate carried by the air; PA1 mass exchange surfaces handily and easily variable according to need; PA1 a fairly good compactness with a hugh "area density", i. e. a high ratio mass transfer surface to volume; and PA1 particularly when using hygroscopic solutions like LiCl absence of hygienic problems upon the membrane surfaces facing air, due to the bactericide and bacteriostatic activity of LiCl preventing any micro-organism to grow.
In all bases it is necessary to put into service high efficiency filters in order to avoid carryover of solution droplets in the handled air stream which often may cause in ducts a corrosion phenomena.